Description:
------------
see the code below
the first block code's output i think will be: NULL & FALSE

As i think:
the code:
$a["a"]["b"];
will equal to 
array('a'=>array("b"));

may be i wrong? or that's a bug??


Reproduce code:
---------------
<?php
# First block
$a[] = "abc";
print_r($a);

// may be wrong here
echo $a[0][2]; // output: c, may be "null"?
echo isset($a[0][2]); // output: 1 (true), may be "false"?

######################

# Second block
$a["1"] = "123";
$a["1"]["2"] = 'abc';

print_r($a);
echo $a[1]; // output:12a, may will be "123"($a["1"]) ??
?>


Expected result:
----------------
Array
(
    [0] => abc
)

Array
(
    [0] => Array
           (
             [2] => abc
           )
    [1] => 123
)
12a


Actual result:
--------------
Array
(
    [0] => abc
)
c1

Array
(
    [0] => abc
    [1] => 12a
)
12a